June 3, 2010

And then in 2010 a funny thing happened…his strikeout rate dropped from 9.7 per nine innings entering this season to a still respectable but substantially lower 7.8 per nine in 2010. To hear a local writer tell the story (“Fewer Strikeouts Can Lead to More Wins”) Gonzalez’s turnaround in 2010 can in large part be traced back to his strikeout rate falling by nearly 20%. …

ERA+: “ERA measured against the league average, and adjusted for ballpark factors. An ERA+ over 100 is better than average, less than 100 is below average.”

“tRA+ is equal to [((lgTRA – tRA`) / lgTRA) + 1] * 100. This formula puts tRA+ on the same scale as wOBA+’

“tRA involves assigning run and out values to all events under a pitcher’s control and coming up with an expected number of runs allowed and outs generated in a defense and park neutral environment. tRA is on a R/9 scale.”

FIP: “Fielding Independent Pitching, a measure of all those things for which a pitcher is specifically responsible. The formula is (HR*13+(BB+HBP-IBB)*3-K*2)/IP, plus a league-specific factor (usually around 3.2) to round out the number to an equivalent ERA number. FIP helps you understand how well a pitcher pitched, regardless of how well his fielders fielded. FIP was invented by Tangotiger.”

xFIP: “Expected Fielding Independent Pitching. This is an experimental stat that adjusts FIP and “normalizes” the home run component. Research has shown that home runs allowed are pretty much a function of flyballs allowed and home park, so xFIP is based on the average number of home runs allowed per outfield fly. Theoretically, this should be a better predicter of a pitcher’s future ERA.”